Preparation of Insulating Aluminum Nitride Film by Enhanced Shielded Vacuum

为了制备高绝缘性、高导热、可用于电力器件的AlN薄膜，研制了一种新型的反应真空电弧沉积系统。在屏蔽法(S-CAD：屏蔽式阴极弧沉积)中，我们发现采用不同的衬底偏压可以制备出不同晶向的透明氮化铝薄膜。此外，S CAD还可用于制备其他氮化物和氧化物(AlO_2、TiN、TiO_2、CrN、ZnO等)的各种无滴薄膜。然而，S-CAD存在沉积速率下降1/3~1/5的问题。为了提高沉积速率，设计了外加磁场引导屏蔽层后的离子聚焦到衬底的增强屏蔽法(ES-CAD)，并制作了系统装置。在优化了磁场结构和磁通密度后，ES-CAD的沉积速度是S-CAD的5倍以上，甚至快于无屏蔽的常规方法，并建立了采用超导屏蔽的改进型ES-CAD(ES-CAD)，以获得更快的沉积速度。由于超导体的迈斯纳效应，阴极发射的离子被绕过的磁场有效地传输到衬底上。ES-CAD的沉积速率高于ES-CAD。此外，还开发了具有液滴过滤管道的线型和环型磁过滤电弧沉积(FAD)系统。结果发现，虽然环形FAD能够充分过滤液滴，但线性FAD不能过滤液滴。

In order to fabricate the AlN film, which exhibits high electrical insulation property with high thermal conduction and is available for of electric power device, which is available for electric power devices, new reactive vacuum arc deposition system was developed. In the shielded method (S-CAD: shielded cathodic arc deposition), we found that the transparent AlN films with different crystalline orientations could be prepared by using different substrate bias. The S-CAD was further available to prepare various droplet-free films of other nitride and oxides (AlO_2, TiN, TiO_2, CrN, ZnO, etc.). However, the S-CAD has a problem that the deposition rate decreases by 1/3 to 1/5. Then, in order to increase the deposition rate, the enhanced shielded method (ES-CAD) in which the ions behind the shield were conducted and focused to the substrate by external magnetic field, was designed and the system apparatus was fabricated. After optimizing the magnetic filed configuration and magnetic flux density, the deposition rate in ES-CAD was more than 5 times as high as that in S-CAD, and was even faster than that in the non-shielded conventional method.The improved ES-CAD (ES-CAD) in which the superconductor shield employed was then build, in order to obtain much faster deposition rate. The ions emitted from the cathode were effectively transported to the substrate by the detoured magnetic filed due to meissner effect of the superconductor. ES-CAD had higher deposition rate than ES-CAD. Furthermore, linear and torus type magnetically filtered arc deposition (FAD) systems having droplet filtering duct, were developed. As a result, it was found that the liner-FAD was not able to filter the droplets, although the torus-FAD was able to filter the droplets sufficiently.